Prussian Blue

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Illustration of Prussian Blue removing radioactive cesium and thallium


What is Prussian blue?

Prussian blue is a pill that can help remove radioactive cesium and thallium from people’s bodies.

Illustration of how Prussian blue works


How does Prussian blue work?

Prussian blue traps radioactive cesium and thallium in the intestines to keep them from being absorbed by the body.

These radioactive materials move through the intestines and pass out of the body (excrete) in bowel movements. Getting these materials out of the body help limit the amount of time they expose the body to radiation.

Prussian blue reduces the biological half-life of cesium from about 110 days to about 30 days. The biological half-life is the amount of time it takes for the radioactive material to leave the body, which decreases its harm.

  • Prussian blue reduces the biological half-life of thallium from about 8 days to about 3 days.
What is Prussian Blue Image


Who can take Prussian blue?

The drug is safe for most adults, including pregnant women, and children (2-12 years). Experts have not yet determined dosing for infants (ages newborn-2years)

Before you take Prussian blue talk to your doctor if you have

  • constipation
  • blockages in the intestines
  • other stomach problems

Before taking Prussian blue, you should tell your doctor about any medicines you are taking.

Prussian Blue how given illustration


How is Prussian blue given?

Prussian blue comes in 500-milligram capsules that patients can swallow whole. If you cannot swallow pills, you can break the capsule and mix the contents in food or liquid. This may cause your mouth or teeth to turn blue during treatment.

What are the side effects of Prussian blue?

The most common side effects of Prussian blue are upset stomach and constipation. You can easily treat these side effects with other medications.

You may have blue feces (stool) while you take Prussian blue.

Prussian Blue pill illustration


Where can I get Prussian blue?

You can only obtain Prussian blue by prescription.

People SHOULD NOT take Prussian blue artist’s dye in an attempt to treat themselves. This type of Prussian blue is not a treatment for radioactive contamination and can be harmful.

More detailed information on Prussian blue can be found at the FDA Websiteexternal icon.

Page last reviewed: April 2, 2021
Content source: National Center for Environmental Health (NCEH), Emergency Management, Radiation, and Chemical Branch